The desire for improved security systems and methods that can reliably detect and identify individuals has increased in recent years. Some security systems, for example, use a person's fingerprint or retinal image as a means for determining the person's identity. Such systems, however, cannot be concealed and are relatively intrusive, as they require active participation by the individual being identified. Other methods involve obtaining images of an individual and analyzing the images for characteristics that are indicative of the individual's identity. Such methods typically use standard video images obtained at visible wavelengths. Consequently, the targeted individual appears in the images along with any clothing or other material on or around their body (for example, shirts, sweaters, jackets, pants, skirts, briefcases, backpacks, purses, and so on). These materials often conceal or obfuscate the underlying body of the individual, making the identification procedure undesirably difficult and often unreliable. Accordingly, there is a need for improved imaging systems and methods for unobtrusively obtaining high quality images of a clothed subject's body and using such images to determine the identity of the subject or to perform other analyses of the subject's body.